多层螺旋CT胸部增强扫描的优化选择

目的：探讨多层螺旋CT胸部增强扫描最佳的对比剂注射流率和扫描方式。方法：80例CT胸部增强扫描随机分为4组，每组20例。组1、2、3、4注射流率分别为3.5ml/s、3.5ml/s、4.0ml/s、4.0ml/s；组1、3从肺尖向膈肌扫描；组2、4为膈肌向肺尖扫描。对比剂300mg I/ml，总量80ml。扫描延迟18s，平均扫描时间11.4s。扫描范围平均200mm。评价主动脉和肺动脉增强CT值、上腔静脉伪影和患不适感。结果：各组大血管强化CT值均数在250HU以上。3.5ml/s组和4ml/s，以及2种不同的扫描方向，其大血管总体增强程度均无显性差异（P＞0.05)。上腔静脉伪影以从膈肌向肺尖扫描为少（P＜0.05)。对比剂注射流率增加，伪影亦增加（P＜0.05)。组1和组2，患均无不良反应；组3和组4，各有1例患诉注射局部不适感。结论：以3.5ml/s注射流率从膈肌向肺尖部扫描，是多排螺旋CT胸部增强扫描较好的扫描方式。

The optimization of enhancement on chest with multi-slice CT

Objective:To investigate the optimal parameters of injection rate and enhancement scanning mode. Methods :Eighty patients with chest CT were divided into 4 groups randomly (20 patients in each group).In group 1 and 3,the scanning was performed from the apex to the diaphragm at a rate of 3.5 ml/s and 4 ml/s respectively.In group 2 and 4,the scanning direction was opposite to the group 1 and 3 at the same injected rate as group 1 and 3 respectively.CT attenuation values of aorta and pulmonary artery enhanced were measured.The followings were observed as the artifacts in superior vena cava and the side effects produced by contrast medium used.Results:The enhanced degree of great vessels was not significantly different between the groups with the various injection rates or scanning directions.The artifacts in SVC were less in the scanning direction from the dome of the diaphragm to the apex ( P <0.05). The higher the injection rate,the more the artifacts ( P <0.05).Side effects appeared in only one case respectively in group 3 and 4 while no side effects occurred in group 1 and 2.Conclusion:It is a better contrast enhancing mode of chest spiral CT to scan from the dome of the diaphragm to the apex at a rate of 3.5 ml/s.